1. Field of the Invention
The present invention relates to a synthetic resin pipe including, in two pipe end portions thereof, a joint for connecting the synthetic resin pipe to another synthetic resin pipe.
2. Description of the Related Art
Conventionally, there is a well known pipe structure in which a separately produced pipe joint is united integrally with a pipe end portion of a synthetic resin pipe.
For example, there exists a synthetic resin pipe with a joint member which can be produced in the following manner. Firstly, over the outer peripheral surface of the pipe end portion of a synthetic resin pipe a half section of a cylindrical-shaped joint member is fitted. The joint member has an inner peripheral surface formed with a shape identical to that of an outer peripheral surface of a synthetic resin pipe end portion.
The pipe end portion and the joint member are joined together with adhesives, or, a liquid-state monomer, which can be polymerized and hardened quickly at room temperature. The adhesive is inserted into a clearance between the joint member and the pipe end portion and hardens to connect the joint member and pipe end portion together to form a synthetic resin pipe with an integrally formed joint member.
However, the above-mentioned conventional method for connecting a separately produced joint member to the end portion of a synthetic resin pipe is problematic and difficult.
Additionally, the outer peripheral surface of the pipe end portion of the synthetic resin pipe is not always identical with the inner peripheral surface of the joint member. In many cases, molding gaps can be present between the inner and outer peripheral surfaces. In such cases, it is difficult to join the surfaces together in a manner such that a watertight condition can be maintained.
In view of the foregoing and other problems, disadvantages, and drawbacks of the conventional synthetic resin pipes with joints, the present invention has been devised, and it is an object of the invention to provide a structure for eliminating the drawbacks found in the above-mentioned conventional synthetic resin pipe with a joint.
In order to attain the above and other objects, a synthetic resin pipe with a joint is provided such that a given joint portion is formed integrally with a synthetic resin pipe at the time the synthetic resin pipe is molded, thereby eliminating the need to connect a separately formed joint to the pipe end portion of the synthetic resin pipe after the synthetic resin pipe is molded. Further, when connecting together two synthetic resin pipes of this type, the other synthetic resin pipe may be simply inserted into one synthetic resin pipe, i.e., their mutual connection can be completed with a very simple one touch operation.
In attaining the above and other objects, according to the invention, there is provided in a first aspect a synthetic resin pipe with a joint, including a pipe end portion Pa to be connected including an open guide cylinder 11 (e.g., see FIGS. 1-6 for exemplary non-limiting embodiments), a large-diameter cylindrical portion 12 formed in a deep portion thereof continuous with the open guide cylinder 11 and having a diameter larger than front and rear walls extending in the axial direction of the pipe, and an outwardly facing projection 14 disposed in a portion of the large-diameter cylindrical portion 12.
Further included is a separately produced engaging ring R having a non-annular or substantially C-like shape when viewed from the side surface. The engaging ring R includes an inclined guide surface 31 having a large inside diameter in the width-direction on a side end face 31a and having a small inside diameter on a deep side. The engaging ring R further includes a securing stepped portion 32 formed on the deep side, a plurality of cut-out portions 33, formed by cutting out the inclined surface 31, and a projection 34 projecting from a portion of the outer peripheral surface of the engaging ring R.
Another pipe end portion Pb to be connected includes an inclined cylinder 21 with a diameter larger on the deep side than on the end face, a securing stepped portion 22 formed on the rear surface of the inclined cylinder 21, and a plurality of projecting portions 23, provided at the peripheral-direction positions of the rear portion of the inclined cylinder 21 that correspond to the cut-out portions 33, of the ring R.
The engaging ring R is inserted into the inside portion 13 of the large-diameter cylindrical portion 12 of one pipe end portion Pa such that the large-diameter side end face 31a of the inclined guide surface 31 is situated on the entrance side of the pipe end portion Pa and also such that the projection 34 on the outer peripheral surface of the ring R is fitted with the inner surface recessed portion of the outwardly facing projection 14 of the large-diameter cylindrical portion 12.
In providing the above-structure of the invention, the other pipe end portion Pb may include, on the deep side of the portion where the projecting portion 23 is provided, a waterproofing ring 25 which can tightly contact the inner peripheral surface of the open guide cylinder 11 formed in one pipe end portion Pa.
Alternatively, the outer peripheral surface of the deep-side cylindrical portion of the other pipe end portion Pb where the projecting portion 23 is provided may be formed substantially equal in diameter to the inner peripheral surface of the open guide cylinder 11 provided in one pipe end portion Pa, and annular recessed grooves 26 may be formed in the outer peripheral surface of the present deep-side cylindrical portion for fitting waterproofing rings 25.
One or both of the cut-out portions 33 of the ring R and the projecting portions 23 of the other pipe end portion Pb may be formed to include, in the circumferential direction of the ring (R) or the other pipe end portion Pb, the inclined surfaces 23a, 33a for allowing their opposite connecting partners to slide together easily.
In addition, the synthetic resin pipe according to the invention may have a smooth outer shape or an unevenly corrugated outer shape. When the synthetic resin pipe has an unevenly corrugated outer shape, the corrugated shape may be spiral or annular. Further, regarding the corrugated shape of the unevenly corrugated synthetic resin pipe, the raised and recessed portions both may be round, or alternatively, the raised portions may be angular and the recessed portions may be round.
In a connection of respective pipe end portions, (e.g., two synthetic resin pipes of this type), the pipe end portion Pb of one synthetic resin pipe may be simply inserted into the pipe end portion Pa of another synthetic resin pipe in the pipe""s axial direction.
In this insertion operation, the other pipe end portion Pb contacts the inclined guide surface 31 of the ring R through the inclined cylinder 21 formed in the leading end portion. The other pipe end portion Pb moves into the deep portion of one pipe end portion Pa while spreading the inclined guide surface 31 in the peripheral direction of the ring R.
When the securing stepped portion 22 of the other pipe end portion Pb passes through the inclined guide surface 31, the spreading force in the peripheral direction is halted with a snap, thereby returning the ring R to its original state and signaling the end of the inserting operation with a snapping sound.
Thus, the securing stepped portion 22 of the other pipe end portion Pb is engaged with the securing stepped portion 32 formed on the deep side of the inclined guide surface 31 of the ring R. This prevents the other pipe end portion Pb from moving in a reverse direction and disconnecting.
At this point, the plurality of projecting portions 23 of the other pipe end portion Pb are fitted into the plurality of cut-out portions 33 of the ring R, thereby preventing the other pipe end portion Pb from moving in the peripheral direction.
Thus, to connect together the respective pipe end portions of the two synthetic resin pipes according to the invention, a synthetic resin pipe may be simply inserted into another synthetic resin pipe in the pipe""s axial direction. That is, the mutual connection between the two synthetic resin pipes can be completed with a very simple one-touch operation.
To disconnect the mutual connection between the two synthetic resin pipes, if the pipe end portion Pb of the other synthetic resin pipe is rotated in the peripheral direction with respect to the pipe end portion Pa of one synthetic resin pipe, then the projecting portions 23 of the other pipe end portion Pb fitted to the cut-out portions 33 of the ring R are rotated, thereby to produce a rotating force in the peripheral direction. As a result, the other pipe end portion Pb is released from the cut-out portions 33 of the ring R onto the inclined guide surface 31 thereof while increasing the diameter of the ring R. The increased diameter of the ring moves the securing stepped portion 32 of the ring R beyond the diameter of the securing stepped portion 22 on the back surface of the inclined cylinder 21, thereby to remove the mutual engagement between the securing stepped portion 32 and securing stepped portion 22. Thus, in this state, if the other pipe end portion Pb is pulled out from one pipe end portion Pa, then the two pipe end portions Pa and Pb can be disconnected.
Therefore, to disconnect the two synthetic resin pipes, one pipe may be rotated once in the peripheral direction with respect to the other pipe and, subsequently, the one pipe may be extracted from the other pipe in the pipe""s axial direction. That is, the mutual connection between the two synthetic resin pipes can be disconnected by a simple two-stage operation.
The present disclosure relates to subject matter contained in Japanese Patent Application No. Hei. 10-288789, filed on Sep. 25, 1998, and which is expressly incorporated herein by reference in its entirety.